Less than 20 years ago the field of cannabis and the cannabinoids was still considered a minor, somewhat quaint, area of research. A few groups were active in the field, but it was already being viewed as stagnating. The chemistry of cannabis was well known, Δ9-tetrahydrocannabinol (Δ9-THC), identified in 1964, being the only major psychoactive constituent and cannabidiol, which is not psychoactive, possibly contributing to some of the effects. These cannabinoids and several synthetic analogs had been thoroughly investigated for their pharmacological effects. Their mode of action was considered to be non-specific. The reasons for this assumption were both technical and conceptual
